Q13. Do all patients with Kallmann syndrome develop osteoporosis ?

There is unfortunately an increased risk of developing a condition called osteoporosis, otherwise known as brittle bone disease, at some time in your life. Osteoporosis is characterised by bones which are weaker and more brittle than healthy, strong bones and are therefore more liable to fracture. It is commonly encountered amongst post-menopausal women and the elderly as well as amongst the hypogonadal population, including those with Kallmann's syndrome.

In the answer to Question 12, we saw how bones grow and strengthen during puberty. We also saw how bones calcify with the help of testosterone or oestrogen and why without these hormones, they lack the strength of normal bones. Generally speaking, the greater the calcification, the stronger the bone. In the case of hypogonadism, osteoporosis occurs as a result of insufficient calcification. Therefore, the sooner you start hormone replacement therapy, the sooner bone calcification can begin and the stronger the bones become. The risk is generally lower for those diagnosed and treated as children or adolescents. Without treatment, the risk of osteoporosis is much greater.

Compare the cross-sections of a normal, healthy bone and an osteoporotic bone (Figure 13). Although the entire skeleton is affected by osteoporosis, it is the spine and hips which are the most involved. There is some bone loss involved with osteoporosis: bones walls are thinner (item 1), the bone marrow cavities are larger (item 2) and the spaces or pores in the spongy bone tissue are larger (item 3).

Bone loss in osteoporosis.

The extent of osteoporosis can be minimised by taking vigorous exercise, calcium supplements in the form of tablets and through testosterone or oestrogen therapy. These and other forms of treatment are discussed in more detail in the answer to Question 22.